1. Field of the Invention
The present invention relates to identifying extreme behavior in elements of a network. Extreme behavior may be generated by a target event which, for example, may be fraudulent use of the network, however the present invention has application in detecting other target events which cause extreme behavior in elements of a network.
2. Description of the Related Technology
Fraud is a serious problem in modern telecommunications systems, and can result in revenue loss by the telecommunications service provider, reduced operational efficiency, and the loss of customers that switch to networks that are perceived to be more secure. In the highly competitive telecommunications sector, any provider that can reduce revenue loss resulting from fraud—either by its prevention or early detection—has a significant advantage over its competitors.
Fraudulent activity is frequently associated with unusual increases in the activity of particular elements in a network. These include switches (which are used to route data around the network), and data sources and sinks (typically individual telephones or modems in the case of telecommunications networks). In most cases, the number of elements in a network is so large that the level of normal activity associated with each cannot be assessed. For example, there are several tens of billions of telephones connected to the global telecommunications network, meaning that impractically large amounts of storage would be required to maintain the statistics necessary to monitor the level of activity associated with each individually. Despite these difficulties, fraud often results in unusually high activity in a frequently small set of network elements, and identifying these elements is important in recognising repeated attacks by individual fraudsters and the weaknesses in the network that they are exploiting. It is believed that there are no techniques known in the prior art that detect fraud by identifying unusual increases in the number of calls to small sets of numbers on the global telecommunications network.